This version 1st September 1998
To get the latest version of Tidy please visit the original version of this page at: http://www.w3.org/People/Raggett/tidy. Courtesy of Netmind, you can register for email reminders when new versions of tidy become available.
When editing HTML it's easy to make mistakes. Wouldn't it be nice if there was a simple way to fix these mistakes automatically and tidy up sloppy editing into nicely layed out markup? Well now there is thanks to Hewlett Packard's Dave Raggett. HTML TIDY is a free utility for doing just that. It also works great on the attrociously hard to read markup generated by specialized HTML editors and conversion tools, and can help you identify where you need to pay further attention on making your pages more accessible to people with disabilities.
Tidy is able to fix up a wide range of problems and to bring to your attention things that you need to work on yourself. Each item found is listed with the line number and column so that you can see where the problem lies in your markup. Tidy won't generate a cleaned up version when there are problems that it can't be sure of how to handle. These are logged as "errors" rather than "warnings".
Tidy corrects the markup in a way that matches where possible the observed rendering in popular browsers from Netscape and Microsoft. Here are just a few examples of how TIDY perfects your HTML for you:
is mapped to
<p>here is a para <b>bold <i>bold italic</b> bold?</i> normal?
is mapped to
<p>here is a para <b>bold <i>bold italic</i> bold?</b> normal?
<h1><i>italic heading</h1> <p>new paragraph
In Netscape and Internet Explorer this causes everything following the heading to be in the heading font size, not the desired effect at all!
Tidy maps the example to
<h1><i>italic heading</i></h1> <p>new paragraph
<i><h1>heading</h1></i> <p>new paragraph <b>bold text <p>some more bold text
Tidy maps this to
<h1><i>heading</i></h1> <p>new paragraph <b>bold text</b> <p><b>some more bold text</b>
Tidy maps this to
<hr> <h1>heading</h1> <h2>sub</h2> <hr> <h2>heading</h2>
Tidy maps this to
<body> <li>1st list item <li>2nd list item
is mapped to
<body> <ul> <li>1st list item</li> <li>2nd list item</li> </ul>
Tidy inserts quote marks around all attribute values for you. It can also detect when you have forgotten the closing quote mark, although this is something you will have to fix yourself.
Tidy has a comprehensive knowledge of the attributes defined in the HTML 4.0 recommendation from W3C. This often allows you to spot where you have mistyped an attribute or value.
Tidy will even work out which version of HTML you are using and insert the appropriate DOCTYPE element, as per the W3C recommendations.
This is something you then have to fix yourself as Tidy is unsure of where the > should be inserted.
You can choose which style you want Tidy to use when it generates the cleaned up markup: for instance whether you like elements to indent their contents or not.
Tidy offers you a choice of character encodings: US ASCII, ISO Latin-1, UTF-8 and the ISO 2022 family of 7 bit encodings. The full set of HTML 4.0 entities are defined. Cleaned up output uses HTML entity names for characters when appropriate. Otherwise characters outside the normal range are output as numeric character entities.
Tidy offers advice on accessibility problems for people using non-graphical browsers. The most common thing you will see is the suggestion you add a summary attribute to table elements. The idea is to provide a summary of the table's role and structure suitable for use with aural browsers.
Many tools generate HTML with an excess of FONT, NOBR and CENTER tags. Tidy's -clean option will replace them by style properties and rules using CSS. This makes the markup easier to read and maintain as well as reducing the file size! Tidy is expected to get smarter at this in the future.
XML processors compliant with W3C's XML 1.0 recommendation are very picky about which files they will accept. Tidy can help you to fix errors that cause your XML files to be rejected. Tidy doesn't yet recognize all XML features though, e.g. it doesn't yet understand CDATA sections or DTD subsets.
<html> <head> </head> <body> <p> para which has enough text to cause a line break, and so test the wrapping mechanism for long lines. </p> <pre>This is <em>genuine preformatted</em> text </pre> <ul> <li> 1st list item </li> <li> 2nd list item </li> </ul> <!-- end comment --> </body> </html>
and this is the default style:
<html> <head> </head> <body> <p>para which has enough text to cause a line break, and so test the wrapping mechanism for long lines.</p> <pre>This is <em>genuine preformatted</em> text </pre> <ul> <li>1st list item </li> <li>2nd list item</li> </ul> <!-- end comment --> </body> </html>
tidy [[options] filename]*
HTML tidy is not (yet) a windows program. If you run tidy without any arguments, it will just sit there waiting to read markup on the stdin stream. Tidy's input and output default to stdin and stdout respectively. Errors are written to stderr but can be redirected to a file with the -f filename option.
I generally use the -m option to get tidy to update the original file, and if the file is particularly bad I also use the -f option to write the errors to a file to make it easier to review them. Tidy supports a small set of character encoding options. The default is ASCII, which makes it easy to edit markup in regular text editors.
tidy -f errs.txt -m index.html
which runs tidy on the file "index.html" updating it in place and writing the error messages to the file "errs.txt". Its a good idea to save your work before tidying it, as with all complex software, tidy may have bugs. If you find any please let me know!
To get a list of available options use:
You should see something like this:
options for tidy vers: 11th June 1998 -indent or -i indent element content -omit or -o omit optional endtags -wrap 72 wrap text at column 72 (default is 68) -upper or -u force tags to upper case -clean or -c replace font, nobr & center tags by CSS -raw don't o/p entities for chars 128 to 255 -ascii use ASCII for output, Latin-1 for input -latin1 use Latin-1 for both input and output -utf8 use UTF-8 for both input and output -iso2022 use ISO2022 for both input and output -modify or -m to modify original files -errors or -e show only error messages -f file write errors to file -xml use this when input is in XML -asxml to convert HTML to XML -help list command line options
Input and Output default to stdin/stdout respectively. Single letter options apart from -f may be combined as in: tidy -f errs.txt -imu foo.html
onmouseover="window.status='Mission Statement, \ Our goals and why they matter.'; return true"
You can now set the wrap margin with the -wrap option.
When the output is XML, tidy now ensures the content starts with <?XML version="1.0"?> as required by the W3C Recommendation for XML.
The Document type for HTML 2.0 is now "-//IETF//DTD HTML 2.0//". In previous versions of tidy, it was incorrectly set to "-//W3C//DTD HTML 2.0//".
When using the -clean option isolated FONT elements are now mapped to SPAN elements. Previously these FONT elements were simply dropped.
NOFRAMES now works fine with BODY element in frameset documents.
The code is in ANSI C and uses the C standard library for i/o. The parser is thread-safe although the code for pretty printing the parse tree is not (yet). The parser works top down, building a complete parse tree in memory. Document text is held as Unicode represented as UTF-8 in a character buffer that expands as needed. The code has so far been tested on Windows'95, Windows NT, Linux, MacOS, BeOS, SunOS, Solaris, IRIX and HP-UX, amongst others.
To compile Tidy using gcc, you can use the makefile or simply type:
gcc -o tidy *.c
Dave Raggett <email@example.com> is an engineer from Hewlett Packard's UK Laboratories, and works on assignment to the World Wide Web Consortium, where he is the W3C lead for HTML.